Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler

Dong, Hao; Jiang, Xuguang; Chi, Yong; Yan, Jun

doi:10.1016/j.wasman.2015.08.004

Cited by 35 publications

(13 citation statements)

References 47 publications

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“…Leather wastes have high calorific value (12-14 MJ/kg). However, sulfides are formed during their combustion, Volatile Organic Compounds (VOC) and greenhouse gases may be emitted to the atmosphere [5,8,9]. A final way of dealing with BDC waste is collagen extraction [2,10,11].…”

Section: Introductionmentioning

confidence: 99%

Hazardous Waste Management of Buffing Dust Collagen

2020

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Buffing Dust Collagen (BDC) is a hazardous waste product of chromium tanning bovine hides. The aim of this study was to investigate whether BDC has the desirable properties required of modern fillers. The microstructural properties of BDC were characterized by elemental analysis (N, Cr2O3) of dry residue and scanning electron microscopy (SEM). The BDC was applied (5 to 30 parts by weight) to styrene butadiene rubber (SBR), obtaining SBR-BDC composites. The physicochemical properties of the SBR-BDC composites were examined by Fourier transform infrared analysis, SEM, UV–Vis spectroscopy, swelling tests, mechanical tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The biodegradability of the SBR-BDC composites and their thermo-oxidative aging were also investigated. The filler contributed to increase the cross-link density in the elastomer structure, as evidenced by enhanced mechanical strength. The introduction of a filler into the elastomer structure resulted in an increase in the efficiency of polymer bonding, which was manifested by more favorable rheological and mechanical parameters. It also influenced the formation of stable interfacial bonds between the individual components in the polymer matrix, which in turn reduced the release of compact chromium in the BDC filler. This was shown by the absorption bands for polar groups in the infrared analysis and by imaging of the vulcanization process.

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Section: Introductionmentioning

confidence: 99%

Hazardous Waste Management of Buffing Dust Collagen

2020

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“…Fluidized-bed (FB) combustion technology has been developed as a clean combustion technology for decades. It has been proven to be suitable for most types of fuels . Additionally, it is a low-pollution combustion technology, which makes it promising for fuels such as LWT.…”

Section: Introductionmentioning

confidence: 99%

“…It has been proven to be suitable for most types of fuels. 2 Additionally, it is a lowpollution combustion technology, which makes it promising for fuels such as LWT. In our previous work, rheological characteristics of LWT pipeline transportation were studied to determine if LWTs are suitable for use as a slurry.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Combustion and Emission Characteristics of an Indonesian Lignite Washery Tailing Slurry with a Bituminous Coal in a Bench-Scale Bubbling/Circulating Fluidized Bed Combustor

et al. 2016

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In this study, the combustion and emission characteristics of slurry from an Indonesian lignite washery tailing (LWT) and a bituminous coal were studied and compared in both a bubbling fluidized bed (BFB) and a circulating fluidized bed (CFB). The effects of excess air ratio, feeding rate, secondary air ratio, and secondary air location on the flue gas emissions were analyzed to investigate the optimal operating conditions. The results show that it is feasible to directly fire LWT slurry in a CFB. The temperature of the dense-phase bed firing the LWT slurry can reach 800 °C but is lower than that of a normal BFB/CFB firing coal. Both SO2 and NO emissions of bituminous coal are higher than those of LWT slurry, but their emission characteristics are still below the limits for both EU and Chinese regulations. Improved emission characteristics are observed when firing LWT slurry and coal in CFB compared to BFB. Two main differences were found between LWT slurry and coal: (1) Low primary air (PA) flow rates facilitate the defluidization of the FB combustor when firing LWT slurry. (2) High feeding rates of LWT slurry may reduce the temperature along FB instead. These factors should be paid special attention when designing and operating an FB system. Optimal secondary air (SA) ratios were determined for both LWT slurry and coal. The SA should not be located near the distributor. All of the analyses in this study provide useful information for the design and operation of a commercial FB system.

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“…In Ca-rich fuel, chromium was probably oxidized to form calcium chromate during combustion. , An effective method to suppress the oxidation of chromium is to decrease the free CaO content, by separating Ca-rich components from the fuel or enhancing the interactions of Si/Al- or P-compounds with free CaO. , In addition, increasing the operating temperature could partly decrease the fraction of chromate in ash residues. This effect was attributed to the rapid decomposition of oxidized CaCrO 4 .…”

Section: Resultsmentioning

confidence: 99%

Further Insight into the Formation and Oxidation of CaCr₂O₄ during Solid Fuel Combustion

Shi

Yang

et al. 2018

Environ. Sci. Technol.

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The control of toxic chromate (Cr) formation is still a significant challenge in solid fuel combustion. In particular, the mechanism of chromium transformation from Cr to chromate or other unoxidized forms remains unclear. The present study confirms the formation of a significant unoxidized Cr-containing compound CaCrO(Cr) during solid fuel combustion. Experiments were conducted, for the first time, to clarify the mechanism of CaCrO oxidation, which is quite different from CrO oxidation. The findings demonstrate that CaCrO was formed at temperatures above 1200 K, through rapid decomposition of CaCrO or slow and direct interaction between CaO and CrO. Compared to CrO, CaCrO could be oxidized at lower temperatures under the influence of free CaO. In the absence of free CaO, the oxidation of CaCrO was minimal; however, in the presence of CaSO, calcium in the form of CaCrO participated in the oxidation of CaCrO. Thus, chromium in the form of CaCrO was more likely to be oxidized when CaCrO-containing fly ash was reheated. Fortunately, CaCrO showed slight basicity on the surface, allowing it to react with acidic gases. Accordingly, measures were proposed to suppress the oxidation of CaCrO by stimulating the reactions between CaCrO and acidic substances, like SO and Si/Al-compounds. These compounds competed with chromium at high temperatures to react with calcium in the fly ash and in CaCrO. As a result, the unoxidized chromium was transformed into highly stable CrO or CaCr (SiO).

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Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler

Cited by 35 publications

References 47 publications

Hazardous Waste Management of Buffing Dust Collagen

Hazardous Waste Management of Buffing Dust Collagen

Comparison of Combustion and Emission Characteristics of an Indonesian Lignite Washery Tailing Slurry with a Bituminous Coal in a Bench-Scale Bubbling/Circulating Fluidized Bed Combustor

Further Insight into the Formation and Oxidation of CaCr₂O₄ during Solid Fuel Combustion

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Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler

Cited by 35 publications

References 47 publications

Hazardous Waste Management of Buffing Dust Collagen

Hazardous Waste Management of Buffing Dust Collagen

Comparison of Combustion and Emission Characteristics of an Indonesian Lignite Washery Tailing Slurry with a Bituminous Coal in a Bench-Scale Bubbling/Circulating Fluidized Bed Combustor

Further Insight into the Formation and Oxidation of CaCr2O4 during Solid Fuel Combustion

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Further Insight into the Formation and Oxidation of CaCr₂O₄ during Solid Fuel Combustion